1. Field of the Invention
The present invention generally relates to cooling systems for x-ray diagnostic devices, and in particular, relates to a heat exchanger system for an x-ray generator with a rotary anode x-ray tube.
2. Description of the Related Art
X-ray diagnostic devices frequently incorporate single-tank generators in which the x-ray source and high voltage generating components are combined into one structural unit. During operation, significant amount of heat is typically generated by the device. Various heat exchanger systems for cooling oil-filled single-tank generators are known. Examples of heat exchangers developed for mobile x-ray apparatus are described in Applicant's co-pending German Patent Applications DE 102 22 267 A1 and DE 103 42 435 A1, which are hereby incorporated by reference in their entirety. In many of these devices, heat generated by an x-ray tube and the associated generator circuit is dissipated by a coolant circuit or heat exchanger located in the generator tank. The heat exchanger is typically disposed in the oil filling of the tank in the form of a spiral tube. This type of heat exchanger configuration has proven suitable for use with stationary anode x-ray tubes in which nearly the entire heat generated by the x-ray tube is dissipated via thermal conduction within the stationary anode to the surrounding oil that fills the generator tank.
In addition to stationary anodes, rotary anode-type x-ray tubes are also frequently used in x-ray diagnostic devices. Rotary anode x-ray tubes are well known and they generally include a rotating anode plate that is mounted within a vacuum housing and rotatably journalled by means of a magnetic bearing. When a rotary anode tube with a glass jacket is used in a single-tank generator, the heat generated is often many times that of devices with a stationary anode tube. During full-load operation, the majority of heat generated by the rotating anode tube is typically dissipated by means of thermal conduction of the glowing anode plate to the medium surrounding the glass jacket of the rotating anode tube. Because of the compact design of electronic components in a generator tank, components in close vicinity to the anode of the rotating anode tube are likely to be heated up by the thermal radiation emanating from the anode plate.
Thus, it will be appreciated that there is a need for an improved cooling system for a single-tank generator of an x-ray diagnostic device having a rotary anode x-ray tube. To this end, there is a need for an effective heat exchanger for such an x-ray generator which, during full-load operation, effectively dissipates heat from the rotating anode plate of the generator tank.